Generally, an implant is an artificial tooth root made of a material having no rejection reaction to the human body, which is placed into an alveolar bone from which a tooth is missing to replace the root of the missing tooth therewith, and after the artificial tooth root is integral into the alveolar bone, an artificial tooth is fixed to the artificial tooth root through a connection post, thus restoring the original function of the missing tooth.
An implant surgery is performed with an artificial tooth root that is integral into an alveolar bone from which a tooth is missing, a connection post that is accommodated into the artificial tooth root at one end thereof in such a manner that their parts are engaged with those of the artificial tooth root to prevent the rotation thereof, a screw that is accommodated into the interior of the connection post and coupled to the artificial tooth root, and an artificial tooth that is fastened to the front end periphery of the connection post.
The connection post for supporting the artificial tooth has an inclined surface formed on the portion accommodated into the artificial tooth root in such a manner as to be tightly engaged and fastened with the artificial tooth root by means of the screw, and accordingly, even if the screw is separated from the artificial tooth root so as to exchange the artificial tooth, the inclined surface of the connection post tightly engaged with the artificial tooth root is not easily removed from the artificial tooth root, thus delaying the surgery time due to the consumption of lots of time for the separation of the connection post.
If the connection post is not easily separated from the artificial tooth root, it should pull out by means of a tool like pliers, but in this case, shocks may be applied to adjacent teeth, thus causing additional teeth damages.
So as to allow the connection post to be fastened to the artificial tooth root, further, the screw should be inserted into the connection post to perform the fastening, which makes it very inconvenient in performing the implant surgery and causing the escape or loss of the screw at the time when the connection post is separated.
The artificial tooth is obtained by the following procedure. First, a plaster model made with an impression is cut through pin-work, and a wax model is made to have the shape and size of an artificial tooth to be molded through a wax-up. Next, if an investment surrounding the wax model is cured, the wax model is physically removed from the investment to form a mold frame, and a solution is poured into the mold frame to cast the artificial tooth. Finally, oxides formed on the surface of the cast artificial tooth are removed through polishing.
The artificial tooth made through the above-mentioned procedure is fixed to the connection post by means of screw-fastening or cementing.
In case where the impression is made in a patient's oral cavity, however, it is hard to make a real impression. Accordingly, errors may be generated in making the impression, which will sequentially occur in the model making, pin-work, wax-up, investment, casting and polishing, thus failing to ensure the fitness and passivity of the artificial tooth to cause the artificial tooth to be escaped after the implant surgery.
Since the artificial tooth is cast with the complicated procedure, further, a long period of time is needed until the implant surgery is completely finished, which gives many inconveniences to the patient.
Furthermore, the artificial tooth is coupled to the connection post by means of screw-fastening or cementing. In case of the screw-fastening, the screw may become loose or broken by means of lateral force and occlusal force (vertical pressure, lateral pressure and rotary pressure) applied to the artificial tooth when chewing operations are repeatedly conducted after the implant surgery, and in case of cementing, it is not easy to perform repair and correction of the artificial tooth and to conduct transition with which the implant is extended to adjacent teeth.